Spectroscopy refers to the measurement of a quantity based on the interaction between radiation and matter as a function of wavelength or frequency of the radiation. An optical spectrometer is a device that irradiates a sample and analyzes reflected/scattered or transmitted radiation by frequency (or wavelength) components and by their power or intensities. In general, there are two types of spectrometers, dispersive and non-dispersive (e.g. discrete filter or interferometric).
As known in the art of spectroscopy, there are a variety of effects that can cause broadband distortion of the absorption spectrum. Such effects can include, but are not limited to, optical scattering, broadband absorption, scattering due to surface morphology and/or topology.